Immunochromatography is a kind of mature technique for on-site rapid detecting. A conventional immunochromatographic strip 4 is shown in FIG. 1, and contains the following components: an analytical membrane (mainly nitrocellulose membrane) 101, a conjugate pad (mainly glass fiber) 102, a sample pad 103 (mainly glass fiber or absorbent paper) and an absorbent pad (mainly absorbent paper) 104. The above components are fixed on the sticky substrate 105 with proper overlapping sequence. The overlapping of the above components ensures the continuity of liquid flow on the strip. When performing the detection, the sample is added to the sample pad 103. The sample enters the conjugate pad 102 through penetration and siphon actions to redissolve the marker-biomolecular conjugates therein. Under the siphon effect of absorbent pad 104, the sample and conjugates leave the conjugate pad 102, enter into the membrane 101 and flow toward the absorbent pad 104 inside the membrane 101. During the process, a specific immunologic reaction occurs between conjugates, target analytes, test band 106 and quality control band 107 to generate indicative signals. Markers which are commonly used to generate indicative signals include colloid gold, fluorescein, dye, etc. However, every kind of immunochromatographic strip has to follow the detecting mode of one-to-one, namely, only one analyte can be detected in one assay for one sample. This kind of detecting mode is complex and time-consuming when used for the screening of a variety of target analytes in suspected samples.